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The volume ratio of hydrogen… (Class 10 Science 2026, Q17)

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ScienceCBSE Class 10 · Board exam 2026, set 31/5/1 · 1 mark · MCQ

CBSE Class 10 Science 2026: question 17

Set in the CBSE Class 10 board exam of 2026, paper 31/5/1, section B, question 17, for 1 mark. Try it first; the hints and our step-by-step solution are below.

Q17 · 1 mark · MCQChemical Reactions and Equations

The volume ratio of hydrogen and oxygen gases liberated during electrolysis of water is :

  1. (A)1 : 2
  2. (B)2 : 1
  3. (C)1 : 3
  4. (D)4 : 1

Source: official question paper from cbse.gov.in (PDF). See it in the full 2026 board paper, set 31/5/1.

Hints

Open one hint at a time and try again before the next.

Hint 1

Write the balanced equation for the decomposition of water.

Hint 2

Compare the coefficients of H₂ and O₂.

Step-by-step solution

Each step shows the marks it earns, as an examiner would award them. Checked by an independent re-solve from the question paper.

  1. The electrolysis reaction is .

  2. Two volumes of hydrogen form for every one volume of oxygen, so the ratio is 2 : 1. Answer: (B).

    1 mark

Answer: (B) 2 : 1

Where the marks are

  • Uses the balanced equation to get 2:1 (1 mark)

Revise the chapter

Practise this chapterBoard-style questions from Chemical Reactions and Equations, one at a time, marked against the answer key and marking points.Back to the full paper2026 board paper, set 31/5/1: every question, by section.

The question is transcribed from the official paper; figures are described in words. The solution, hints and chapter tag are ours. Spotted an error? Write tosupport@questionbuddy.in.